1. Field of the Invention
The present invention relates to a protective device and a CCFL driving system used thereon, and more particularly to a protective signal outputted to a control circuit according to a high AC power detected in the high-voltage terminal of a CCFL of the claimed system. The outputted protective signal is used for protecting the control circuit, the protective device of the CCFL, and the CCFL driving system.
2. Description of Related Art
A CCFL (Cold Cathode Fluorescent Lamp) is used as a light source for the backlight module in a LCD panel. CCFLs are driven by a driving circuit such as an inverter. The size of LCD panels are increasing due to progressive technical developments and consumer demand, so that now it is common for two or more CCFLs to be used for illuminating the panel.
In general, a set of the inverters can only light one or two CCFLs, but more inverters are required for driving a plurality of CCFLs as used for a large-sized LCD panel or a large TV LCD screen. Correspondingly, the plural protective circuits are required to protect the inverters and the CCFLs. As such, the cost to manufacture the LCD panel is increasing as well. Additionally, the protective circuit of the conventional scheme is complicated and the circuitry thereof is becoming increasingly complex.